John Naish writes about how scientific studies show that small changes in your behaviour can add years to your life

Can we really make a lasting difference to our health by doing things today that will benefit us in 20 years’ time? We are beginning to reap the results of a number of large-scale health studies that were begun more than two decades ago by far-sighted scientists. They followed thousands of participants for 20 years or more to find out what impact diet, exercise and lifestyle choices had on their health. The results provide us with crucial clues about daily habits we can adopt to ensure good long-term health.

Have sex This seems particularly important for middle-aged men. Those who have intercourse several times a week significantly reduce their risk of suffering a fatal stroke. This is according to researchers at the University of Bristol who spent 20 years monitoring the cardiac health and sexual activity of 914 men in a former mining village in Wales.The men were aged 45-59 when they were first recruited between 1979 and 1983. About one fifth of the volunteers reported they had sex once a month or less; about one quarter had intercourse twice or more a week; and for the remainder the frequency was somewhere between the two. The 25 per cent who had the most sex ultimately suffered the fewest fatal strokes by far, says the Bristol report, in the Journal of Epidemiology and Co mmunity Health.

Exercise gently Sweating and straining at the gym might feel like the best way to make a significant difference to your health, but gentle and easily sustained habits have proved the better bet for your brain in the long term.

Doing moderate exercise every day can cut your risk of developing dementia by about 40 per cent, according to a study that tracked more than 1,200 people living in the town of Framingham, Massachusetts since 1948. People with the lowest levels of physical activity were up to 45 per cent more likely to develop dementia of any type than those who did the most exercise.

The results are bolstered by a 20-year study that followed almost 20,000 female nurses. Dr Zaldy Tan, the Harvard Medical School expert who conducted the study, says that the women who had regularly walked for 30 minutes every day scored significantly better in mental-health tests than those participants who walked for less than 40 minutes a week.

Shun meat — especially processed meats Eating even small quantities of processed meat such as bacon, sausages or salami can increase your likelihood of dying prematurely by one-fifth, researchers from Harvard Medical Schoolrevealed this year, after they analysed the eating habits of more than 100,000 people for 28 years.

Unprocessed red meat also carries a significant risk to your health, the study revealed. A report in the journal Archives of Internal Medicine found that a daily serving of red meat — equivalent to 85g — over the length of the study brought an 18 per cent increased risk of dying from heart disease and a 10 per cent increased risk of dying from cancer. Why is red meat potentially so dangerous? Dr Frank Hu, a co-author of the study, says steak often contains high amounts of saturated fat, while bacon and salami contain large amounts of salt. He adds that replacing red meat with poultry, fish or vegetables, whole grains and other healthy foods could cut our risk of dying prematurely by up to one fifth. The team’s research has also shown that eating a daily serving of 100g of unprocessed red meat can increase the risk of diabetes by 19 per cent, while one daily 50g serving of processed meat over the 28 year study period is linked with a 51 per cent increase in risk.

Make friends at work Feeling isolated and under threat from colleagues is not just upsetting, it can raise your long-term risk of serious illness or early death by around two-and-a-half times, according to a 20-year study by Tel Aviv University, which tracked more than 820 white-collar workers. It found that those who felt surrounded by bullies and backstabbers had 2.4 times the chance of dying during the study. On the other hand, feeling supported and welcomed by co-workers seems to protect our health and wellbeing significantly, Dr Sharon Toker, the lead researcher, says. “We spend most of our waking hours at work, and we don’t have much time to meet our friends during the weekdays,” she says in the journal, Health Psychology. “Work should be a place where people can get emotional support.”

In order to protect our future health, we need to foster warm human connections at home, too. Living alone in middle age can double your chances of developing Alzheimer’s disease, with those most at risk being divorced or widowed, according to a 20-year study of 2,000 people published in the British Medical Journal last December.

Be careful of vitamin supplements There is evidence that some supplements may do more harm than good. German research in the journal Heart warned last month that calcium supplements taken by millions of people every day to fend off osteoporosis can double their risk of heart attacks. And a study in the Journal of the National Cancer Institute has found that men with prostate cancer who take more than seven multivitamins a week are 30 percent more likely to get an advanced and fatal form of the disease. Defenders of supplements maintain, however, that people who choose to take them may be more likely to be ill in the first place.

Be conscientious Being conscientious and obsessed with detail can have significant benefits for your long-term health. This is according to an eight-decade study following more than 1500 American children from the age of 11, called The Longevity Project.

The authors, Howard Friedman and Leslie Martin, consistently found that conscientious people lived significantly longer. Being conscientious, the authors say, involves having a prudent and persistent nature, being well-organised, somewhat obsessive and not, generally, carefree. One of the reasons this works, say Friedman and Martin, is that taking life seriously makes people want to live “more meaningful, committed lives”.

In turn, such people habitually do more to avoid risk and look after their general wellbeing in small, everyday ways, the authors reported. “These people worked hard. They achieved much for their families. They nurtured close relationships. They were persistent, responsible and successful. They were dedicated to things and people beyond themselves.”

Take regular holidays One quarter of us don’t take all of our holiday time (which is, on average, 26 days). Such workaholic habits are bad news for our health. Using information from the Framingham Heart Study, which began in 1948, researchers discovered that women who don’t often take holidays are almost eight times more likely to develop coronary heart disease or have a heart attack than those who took at least two a year. Dr Elaine Eaker, a co-author of the study, says: “The results show how the body reacts to a lifestyle of stress. This is real evidence that vacations are important to your physical health.”

Eat and drink in moderation Long-term studies into the inhabitants of Okinawa, a group of Japanese islands, where people live on average six years longer than those in Britain, show that we might do well to adopt their habit of hara hachi bu. It means stopping eating when you feel 80 per cent full — and thus cutting your calorie intake by about 20 per cent. This restricted intake has been linked in animal studies to longevity.

Drinking in moderation can help your health in decades to come. A 20-year study of 1,800 men and women published in the journal, Alcoholism: Clinical and Experimental Research, has shown that men and women who drink moderately are more likely to live a long life than heavy drinkers and even teetotallers.

The experts from the University of Texas found three drinks a day do no harm. Low-level alcohol consumption like this protects significantly against coronary heart disease, the leading cause of death in developed countries, so its benefits usually outweigh any risks, the panel of leading scientists believe.